This invention is an improvement in known methods of setting, or resetting poles in the ground, ground line treatment of poles or encapsulation of pole treatment chemicals and enhancement of the strength to density ratio, of foam polyurethane resins formed in-situ from polyisocyanate and resin reactive therein. Ground water and detrimental natural soil chemicals are often encountered in pole setting and these affect polyurethane foam formation by undesirably reacting with the polyisocyanate to give a foam of insufficient density and strength.
The present invention is an improvement in the invention disclosed in U.S. Pat. Nos. 3,968,657 to Hannay, 3,564,859 to Goodman and 3,403,520 to Goodman which describe related methods for resetting poles with foam plastic. The entire disclosures of U.S. Pat. Nos. 3,968,657, 3,564,859 and 3,403,520 are incorporated herein by reference.
In brief, U.S. Pat. No. 3,403,520 describes a method of setting pole forms in the ground by making a hole which is only slightly larger than the butt of the pole to be placed in the hole, placing the pole in the hole in the desired position, partially filling the hole with a reaction mixture of a synthetic resin and a blowing agent and permitting the reaction to complete so as to expand the foam and resin into all the space between the pole and the sides of the hole. The expanded resin adheres to and seals to the end of the pole protecting it from moisture, chemicals and rodents and sets the pole in the hole. The expanding resin fills all the voids, surfaces, crevices and notches, both in the sides and bottom of the hole, as well as in the butt of the pole itself.
U.S. Pat. No. 3,564,859 describes a procedure for straightening and refilling the hole. It utilizes the same method as U.S. Pat. No. 3,403,520 for producing foam and for filling the voids resulting when the existing installed pole has been canted or tilted.
U.S. Pat. No. 3,968,657 was an improvement upon these methods by the addition of a non-volitale water-immiscible material to the mixture so that the reaction can take place in the presence of ground water.